Problem: $ -\dfrac{2}{4} \div \left(-\dfrac{6}{9} \div \dfrac{2}{7}\right) = {?} $
Explanation: First, we can simplify the problem: $ -\dfrac{1}{2} \div \left(-\dfrac{2}{3} \div \dfrac{2}{7}\right) = {?} $ Dividing by a fraction is the same as multiply by the reciprocal of that fraction. $ = -\dfrac{1}{2} \div \left(-\dfrac{2}{3} \times \dfrac{7}{2}\right) $ $ = -\dfrac{1}{2} \div \left(\dfrac{-2 \times 7} {3 \times 2}\right) $ $ = -\dfrac{1}{2} \div -\dfrac{14}{6} $ $ = -\dfrac{1}{2} \times -\dfrac{6}{14} $ $ = \dfrac{-1 \times 6}{2 \times -14} $ $ = \dfrac{6}{28}$ Simplify: $ = \dfrac{3}{14}$